Characterization of the binders in the rock art of Cueva La Conga, Nicaragua
Cueva La Conga is the only known painted cave in Nicaragua, in a part of that country about which little is known archaeologically. The rock art, which includes carved rock formations as well as paintings and handprints, may provide clues about the past people and culture of this area. Archaeologists want to know if the paintings were influenced by the Maya to the north, or the Caribbean cultures to the east, or were a purely indigenous development. Determining the age of the paintings will help to understand the possible cultural relationships between known cultures and the rock art of Cueva La Conga. None of the rock art of Nicaragua has been dated before. To radiocarbon date the red, yellow, and purple images, an organic binder must have been used, and that binder has persisted to this day. If this is true, it can be extracted and dated using accelerator mass spectrometry to determine the 14C content. We are using thermally assisted hydrolysis/methylation-gas chromatography-mass spectrometry (THM-GC-MS) to study the composition of the paints to determine if any binder material remains to be dated. We will compare the compositions of the paint and unpainted limestone to determine if a reliable date is likely to be obtained. This is the first comprehensive study where the chemical characterization of the paint was considered in the sampling of the rock art to be dated. We will describe the inherent difficulties of reconciling good analyses with preservation of these irreplaceable and at-risk cultural materials.
rock art, binder, Cueva La Conga, radiocarbon dating, painted cave, Chemistry
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